JPH06305021A - Foamed sheet with satin pattern and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain a foamed sheet in which a satin pattern an be formed with a die surface having a smooth mirror surface and which has high commodity value with a stereoscopic decoration effect having the satin pattern. CONSTITUTION:A recess 21 of a numeral shape is provided on a lower surface of a hot plate 2, and smooth parts 22 of mirror surface state are formed on the lower surface and a bottom of the recess 21 of the plate 2. When a surface temperature of the plate 2 is heated by a heater 3 to 250-270 deg.C, stopped at 15mm separated from a surface of a foamed sheet 1 and a surface of the foamed sheet is melted after 5sec to have glass, the plate is moved down up to a set clearance to compress the sheet 1 to 25% of its thickness. After 4sec, the plate 2 is raised to 100mm from the surface of the sheet 1, the sheet 1 is again compressed by the plate 2, and the plate 2 is then isolated from the sheet 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a foamed sheet having a satin finish on its surface and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, a foamed or non-foamed synthetic resin product, for example, a film, a sheet, a plate, or other molded products, has a smooth mirror-like surface in order to have a glossy surface. It is molded or processed using a press mold or a mold. Further, in order to make the surface of the synthetic resin product a matte satin pattern with no gloss, use a roll, a press mold, or a mold having the surface treated with a satin finish pattern, and use either the mold or the synthetic resin product. Embossing is performed in which one is heated to the softening temperature of the synthetic resin product and pressed.

[0003] For example, a method for embossing a polyolefin foam and a surface-texturing method for a polyolefin foam as described in "Known Conventional Techniques" pages 328 to 329 issued by the Japan Patent Office on August 3, 1982. It has been known.

[0004]

SUMMARY OF THE INVENTION In the above conventional method,
Utilizing the residual heat at the time of foaming by heating, the foam is embossed before it is cooled, or it is embossed with a heating roll such as passing hot water through the embossing roll. Since the surface of the synthetic resin product does not reach a molten state and is pressed in a softened state as described above, it is not possible to form a deep textured satin pattern, and only a product having a poor three-dimensional effect can be obtained. Further, a matte pattern with a smooth mirror surface cannot form a satin finish, and conversely, a mold with a satin finish cannot form a smooth surface.

The present invention solves the above-mentioned problems of the prior art, and is capable of forming a satin-finished pattern with a mold surface having a smooth mirror surface. The foamed sheet having a satin-finished pattern and having a three-dimensional decorative effect has a high commercial value. And its manufacturing method.

[0006]

According to a first aspect of the present invention, there is provided a method for producing a foamed sheet having a satin pattern, wherein the surface of the foamed sheet made of a thermoplastic resin is heated and pressed by a hot plate to form a pattern on the surface of the foamed sheet. In the method of forming characters, after heating the hot plate pressing surface having a smooth portion to press the foamed sheet surface to melt the foamed sheet surface to form a satin finish, releasing from the pressing by the hot plate. Characterize.

According to a second aspect of the present invention, there is provided a method for producing a foamed sheet having a satin pattern, wherein the surface of the foamed sheet made of a thermoplastic resin and having closed cells is heated and pressed by a hot plate to form a pattern / character on the surface of the foamed sheet. In the forming method, the hot plate pressing surface is heated to press the foam sheet surface to melt the foam sheet surface and
Characters are formed, and a groove is formed on the surface of the foamed sheet around the contour of the hot plate, and a raised portion is formed outside the groove.

In a foamed sheet having a satin-finished pattern according to a third aspect, the surface of the foamed sheet made of a thermoplastic resin is heated and pressed by a hot plate to form a satin-finished pattern on the surface of the foamed sheet, and grooves and ridges surrounding the satin-finished pattern. And forming a part.

The details of the present invention will be described below. Examples of the foamed sheet made of the thermoplastic resin as used in the present invention include low density polyethylene, linear low density polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polybutene, and the like.
Or a mixture of two or more thereof, a derivative resin containing 5% or more of a polyolefin resin, that is, an ethylene-acrylic acid amide copolymer, an ethylene-ethyl acrylate copolymer, an ethylene-methyl acrylate copolymer, and the like. Further, a mixture obtained by mixing a synthetic rubber or the like with the above-mentioned one, or polyvinyl chloride or the like can be used, but a material mainly composed of low-density polyethylene is particularly preferable since it is rich in flexibility and easy to process.

The above-mentioned foamed sheet is preferably a cross-linked one because it has fine and uniform cells and excellent strength, and is an unfoamed resin composition containing a foaming agent, a cross-linking agent such as an organic peroxide. After being extruded into a sheet from an extruder and then crosslinked (chemically crosslinked), an unfoamed resin composition in which a foaming agent is mixed without adding a crosslinker is crosslinked by irradiating with ionizing radiation. It may be foamed (radiation cross-linked) at a temperature not lower than its decomposition temperature.

The expansion ratio of the foamed sheet can be used in the range of 2 to 100 times from the viewpoint of workability, heat insulation, cushioning, soundproofing and the like. If the expansion ratio is lower than 2 times, these performances are not exhibited, and if it exceeds 100 times, the practical strength of the foamed sheet is deteriorated and various performances are also deteriorated. Preferably 5
The range is 40 times.

The thickness of the foamed sheet is preferably 3 mm or more in order to obtain a three-dimensional appearance of the embossed portion by the hot plate. The foamed sheet may be composed of a single layer, or several sheets may be bonded together by an adhesive or by heat fusion. In the case where several foam sheets are laminated, those having the same expansion ratio may be laminated, but those having different expansion ratios may be combined depending on the application.

The hot plate used in the present invention is generally used and may have a pattern or characters formed thereon, but the portion where the satin pattern is to be formed needs to be a smooth mirror surface portion. The mirror surface portion may be a picture / character surface,
It may be a part other than the picture / character part.

To form a satin pattern, the hot plate is first heated. Normally, the heating temperature is in the range of about 120 to 400 ° C. on the surface of the hot plate, and is selected according to the type of resin forming the foamed sheet. Next, the surface of the foamed sheet is heated and pressed. When the surface of the foamed sheet is heated to a molten state and pressed with a hot plate, the molten foamed structure under the skin layer is melted and destroyed, and the molten resin once adheres to the hot plate surface, but the pressing surface of the hot plate is Since it is a smooth mirror surface, the adhesive force between the hot plate and the molten resin is weak.

Next, when the pressing is released and the hot plate is released from the foam sheet, the foam sheet resin adhering to the hot plate is peeled from the hot plate, and the peeling force removes the surface of the foam sheet thinly. Form a satin pattern.

In the above method, the heated hot plate was heated while pressing it against the foamed sheet. Before the pressurization, the hot plate heated to the above temperature is brought close to the surface of the foamed sheet for foaming. It is preferable to preheat until the skin layer on the surface of the sheet begins to melt.

When the skin layer starts to melt, the foam sheet is pressed by the hot plate. The pressing depth is selected depending on the thickness of the foamed sheet and the depth or height of the pattern / character, but is preferably in the range of 3 to 80% of the thickness of the foamed sheet. If the depth is less than 3%, the compressive stress of the foamed sheet is small, and the foamed structure inside is less likely to be exposed on the surface, and the satin pattern is less likely to be formed. Further, it is difficult to form a groove and a raised portion on the peripheral edge of the contour of the hot plate, resulting in poor stereoscopic effect. On the contrary, when the depth is more than 80%, the groove on the peripheral edge of the hot plate becomes abnormally deep, and the inner surface of the groove becomes uneven, and it is difficult to form a groove having a uniform depth and width.

The time for pressing the foam sheet at the above-mentioned depth to the hot plate at the above temperature depends on the temperature of the hot plate,
Although it is appropriately selected depending on the type of resin of the foamed sheet, the pressing depth, etc., it is usually about 1 to 60 seconds.

The pressing of the foamed sheet can achieve the purpose by one pressing, but, for example, pressing once to a predetermined depth, releasing the pressing to raise the hot plate, A more distinct matte pattern can be obtained by temporarily stopping the foamed sheet from the surface within a height range of 2 to 6 times the thickness of the foamed sheet, pressing it again to a predetermined depth, and then separating it from the foamed sheet. There are cases. In this way, the pressing with the hot plate may be repeated a plurality of times. By heating and pressing the foamed sheet with the hot plate as described above, the surface of the foamed sheet in contact with the mirror surface portion of the hot plate does not become glossy, and a satin pattern is formed.

Thus, the satin pattern is formed on the portion pressed by the smooth mirror surface portion of the hot plate. However, since the portion not in contact with the mirror surface portion becomes a glossy surface, for example, if the concave portion is formed with a depth such that the bottom surface of the concave portion carved in the hot plate does not contact the surface of the foamed sheet, the convex portion of the foamed sheet obtained can be obtained. The surface can be a glossy surface.

Further, according to the method of the present invention, the surface of the foamed sheet around the contour of the hot plate rises to form continuous raised portions. This is because the compressive stress of the foamed sheet due to the pressing of the hot plate pushes the foamed tissue out of the pressed portion, where the shape is restored in the thickness direction. In addition, the surface of the raised portion is melted by the heat of the hot plate and becomes glossy, so that the portion surrounded by the raised portion has a high-quality product as if it were set in a frame.

Further, according to the present invention, when the edge of the pressing surface of the hot plate is not chamfered and has a rounded corner, a continuous groove is formed in the foamed sheet of the edge portion. It This is because the foamed tissue is pushed out of the pressed portion by the compressive stress of the foamed sheet due to the pressing of the hot plate, but when the pressing is released, the shape is restored in the surface direction of the foamed sheet. Since the foamed sheet surface is in a molten state, at this moment, the foamed sheet at the edge portion receives a restoring pressure in the direction of being pushed back from the outside of the hot plate, and as a result, a groove is formed.

That is, the groove is formed at the edge of the portion pressed by the hot plate, and the raised portion is formed following the groove. Therefore, the portion having the satin pattern surrounded by the raised portion and the groove inside thereof is further enhanced in three-dimensional effect, and a product full of high-class feeling can be obtained. The formation of the groove is more likely to occur as the corners of the edge of the pressing surface of the hot plate are less rounded, and is less likely to appear as the corners are chamfered and rounded.

[0024]

According to the manufacturing method of claim 1, when the surface of the foamed sheet is heated to a molten state and pressed with a hot plate, the molten foamed structure under the skin layer is melted and destroyed, and the molten resin is once melted. Adheres to the hot plate surface. Next, when the pressure is released and the hot plate is released from the foam sheet, the foam sheet resin adhering to the hot plate is peeled from the hot plate, and the peeling force thinly removes the surface of the foam sheet to form a satin pattern. Form. Further, the foamed sheet in the portion not in contact with the mirror surface portion can be a glossy surface.

According to the manufacturing method of the second aspect, a matte pattern is formed on the surface of the foamed sheet in contact with the smooth portion of the hot plate, and the foamed sheet surface around the contour of the hot plate rises to form a continuous raised portion. Is formed. In addition, the surface of the raised portion is melted by the heat of the hot plate and becomes glossy, so that the portion surrounded by the raised portion has a high-quality product as if it were set in a frame. Further, a continuous groove is formed at the edge of the pressing surface of the hot plate, so that a more three-dimensional appearance can be obtained.

Further, the foamed sheet according to claim 3 has an embossed pattern with a three-dimensional effect and a high-grade feeling due to the beautiful satin pattern on the surface and the grooves and ridges surrounding it, so it can be used for various purposes. it can.

[0027]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of the present invention.
As shown in FIG. 1A, the heater 3 is provided on the lower surface of the hot plate support board 5 via the heat insulating material 4, and the hot plate 2 is provided on the lower surface of the heater 3, and the foamed sheet is provided on the press table 8 below the hot plate 2. 1 is placed. 7, 7
Is a clearance adjusting part for regulating the distance between the lower surface of the hot plate 2 and the press table 8 when the hot plate 2 is lowered, and the clearance is set to 8 mm. Reference numeral 6 is a piston for raising and lowering the hot plate.

The hot plate 2 has an oval shape in a plane, and the lower surface thereof has concave portions 21 and 2 inscribed in a number shape.
1 is provided, the lower surface of the hot plate 2 and the recess 2
Both of the bottom surfaces of 1 and 21 are made into a smooth portion 22 in a mirror state. The depth of the recesses 21, 21 is made deeper than the thickness of the foam sheet 1, and when the hot plate 2 is lowered to the set clearance, as shown in FIG. 1B, the surface of the foam sheet 1 and the bottom surfaces of the recesses 21, 21. A gap 24 is formed between the gap and.

The foam sheet 1 is a closed-cell foam made of crosslinked polyethylene (thickness: 24 mm, foaming ratio: 15 times,
An apparent density of 0.07 g / cm ³ ) was used.

The heater 3 was energized to raise the surface temperature of the hot plate to 250 to 270 ° C., lowered to a distance of 15 mm from the surface of the foamed sheet 1, and stopped. When the surface of the foamed sheet 1 melted and became glossy after 5 seconds, the hot plate 2 was lowered to the set clearance as shown in FIG. 1B to compress the foamed sheet 1 by 25% of its thickness. At this time, a gap 24 is formed between the surface of the foamed sheet 1 and the bottoms of the recesses 21, 21. After 4 seconds, the hot plate 2 is raised from the surface of the foamed sheet to 4 times (100 mm) the thickness of the foamed sheet 1, the hot plate 2 is lowered to the set clearance again, and compressed again, and then, as shown in FIG. The plate 2 was lifted and separated from the foam sheet 1.

FIG. 2 is a plan view showing a foamed sheet 11 having a satin finish obtained by heating and pressurizing with the hot plate 2. Characters 13 and 13 are formed as convex portions in an oval press portion. The surfaces of the characters 13 and 13 were smooth glossy surfaces, and the satin pattern 12 was formed on one surface of the other flat portion. Further, a continuous groove 15 having a depth of 0.5 mm was formed in the entire portion corresponding to the peripheral edge of the hot plate 2. Further, a continuous raised portion 14 having a height of 0.2 mm is formed on the outer periphery of the groove 15, and the outer surface of the raised portion 14 has a luster by being melted by the radiant heat of the hot plate.

FIG. 3 is an enlarged view of the portion a of the foamed sheet 11 having the satin finish shown in FIG. 1C. The portion that was in contact with the smooth portion 22 of the hot plate 2 is peeled off when the hot plate 2 is detached. The matte pattern 12 is formed, and the surface of the character 13 that is not in contact with the bottom surface of the recess 21 of the hot plate 2 is a glossy surface 16.

FIG. 4 is an enlarged view of the portion b shown in FIG. 1C. A groove 15 is formed along the contour of the hot plate 2 on the surface of the foam sheet 1 corresponding to the edge portion 23 of the hot plate 2. A continuous raised portion 14 is formed outside the groove 15.

In the foamed sheet 11 having a satin pattern obtained as described above, the glossy characters 13 and 13 are raised, and the other plane portion is a calm satin pattern 12, and the periphery of the satin pattern 12 The groove 15 and the raised portion 14 produce a shadow to give a three-dimensional effect like a picture frame, which gives a sufficient high-class feeling and is aesthetically satisfactory. Therefore, the foamed sheet obtained by the present invention is an interior material due to its beauty,
It can be used for bedding, bath slates, etc.

[0035]

The present invention is configured as described above, and according to the first aspect of the present invention, the satin pattern is formed on the portion pressed by the smooth mirror surface portion of the hot plate. But,
Since the part that does not contact the mirror surface part becomes a glossy surface, if the recessed part is formed with a depth such that the bottom surface of the recessed part engraved on the hot plate does not contact the surface of the foamed sheet, the surface of the protruding part of the resulting foamed sheet will be formed. It can be a glossy surface. In addition, it is not necessary to use a mold having a satin pattern formed on the surface in order to form the satin pattern.

According to a second aspect of the present invention, in addition to the first aspect of the present invention, when the pressing surface edge of the hot plate is not chamfered and has rounded corners, the hot plate Since a groove is formed on the peripheral edge of the contour and a raised portion is formed on the outer side of the contour, the portion having a satin pattern surrounded by the raised portion and the groove on the inner side further enhances the three-dimensional effect, resulting in a product full of luxury. To be

Further, the foamed sheet according to claim 3 has an embossed pattern with a three-dimensional effect and a high-class feeling due to the beautiful satin pattern on the surface and the grooves and ridges surrounding it, so that the interior material is beautiful. It can be used for various purposes such as floor coverings, slats for baths, etc.

[0038]

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing steps of a manufacturing method of the present invention.

FIG. 2 is a plan view showing an embodiment of a foamed sheet obtained by the present invention.

FIG. 3 is an enlarged view of part a of FIG.

FIG. 4 is an enlarged view of part b of FIG.

[Explanation of symbols]

 1: Foamed sheet 2: Hot plate 3: Heater 4: Insulating material 5: Hot plate support plate 6: Piston 7: Clearance adjusting part 8: Press stand 11: Foamed sheet with satin pattern 12: Pear-skin pattern 13: Character 14: Raised part 15: Groove 16: Glossy surface 21: Recessed part 22: Smooth part 23: Edge part 24: Gap

Claims (3)

[Claims] 1. A method for forming a pattern or character on a surface of a foamed sheet made of a thermoplastic resin by heating and pressing the surface of the foamed sheet with a hot plate, thereby heating and foaming a hot plate pressing surface having a smooth portion. A method for producing a foamed sheet having a satin finish, comprising forming a satin finish by pressing the surface of the sheet and melting the surface of the foamed sheet, and then releasing from the pressing by a hot plate. 2. A method for forming a pattern or character on a surface of a foamed sheet made of a thermoplastic resin and having closed cells by heating and pressurizing the surface of the foamed sheet by heating a hot plate pressing surface for foaming. By pressing the surface of the sheet, the surface of the foamed sheet is melted to form a satin finish, and a groove is formed on the surface of the foamed sheet around the contour of the hot plate, and a raised portion is formed outside the groove. A method for producing a foamed sheet having a satin pattern. 3. A surface of a foamed sheet made of a thermoplastic resin is heated and pressed by a hot plate to form a satin finished pattern, and grooves and raised portions surrounding the satin finished pattern on the surface of the foamed sheet. A foamed sheet with a characteristic satin finish.